14C and 10Be dated Late Holocene fluctuations of Patagonian glaciers in Torres del Paine (Chile, 51°S) and connections to Antarctic climate change
14C and 10Be dated Late Holocene fluctuations of Patagonian glaciers in Torres del Paine (Chile, 51°S) and connections to Antarctic climate change
复制标题
DOI：
10.1016/j.quascirev.2020.106541
复制
发表时间：
2020-10
影响因子：
4
通讯作者：
J. García;B. Hall;M. Kaplan;Gabriel Gómez;R. Pol-Holz;V. J. García;J. Schaefer;R. Schwartz
中科院分区：
文献类型：
--
作者：
J. García;B. Hall;M. Kaplan;Gabriel Gómez;R. Pol-Holz;V. J. García;J. Schaefer;R. Schwartz
南半球全新世冰川年代学对于揭示过去的气候变化、中高纬度遥相关以及区域到全球气候强迫具有重要意义。目前，巴塔哥尼亚的大量冰川年表都是基于14C测年，这可能只能提供最大或最小限制日期。在这里，我们将地貌学和地层学与放射性碳 (14C) 和铍 10 (10Be) 表面暴露年龄测年相结合，对萨帕塔、廷德尔和平戈这三个出口冰川进行了表面暴露年龄测年。这些冰川排出智利百内国家公园南巴塔哥尼亚冰原最南端的水（南纬 51°）。经过我们确定的 3200 年的扩张之后。 B.P. 表示，Torres del Paine 冰川在 600 年和 340 年扩张到了全新世晚期的最后一个主要最大值。 B.P.，最终日期为 190 年后重新提前。 B.P.我们使用这些数据以及其他巴塔哥尼亚冰川记录来定义上个千年的早期、中期和末期冰川阶段。这些寒冷事件被温暖的条件所隔开，使得Notofagus森林能够在冰川消退的土地上定居。巴塔哥尼亚和南极半岛几乎同时存在的冰川波动表明，全新世晚期，包括上个千年，南半球温带大部分地区出现了广泛的变冷。我们将这种冷却与南西风向北移动或加强所造成的寒冷海洋大气条件联系起来。这种情况增加了巴塔哥尼亚西部寒冷的南极环极地海水向北的平流，并有利于温暖的环极地深水的上升流减少以及南极半岛周围海冰的扩大。
Southern Hemisphere Holocene glacier chronologies are important for unraveling past climate change, mid-to-high latitude teleconnections, and regional to global climate forcing. At present, a significant number of glacier chronologies for Patagonia are based on14C dating, which may afford only maximum- or minimum-limiting dates. Here, we combine geomorphology and stratigraphy with radiocarbon (14C) and beryllium-10 (10Be) surface exposure-age dating at three outlet glaciers, Zapata, Tyndall, and Pingo. These glaciers drain the southernmost tip of the Southern Patagonian Ice Field at Torres del Paine National Park, Chile (51°S). After an expansion that we date at 3200 yr. B.P., the Torres del Paine glaciers expanded to their last major Late Holocene maxima at 600 and 340 yr. B.P., with the final dated readvance after 190 yr. B.P. We use these data, together with other Patagonian glacier records, to define the early, mid and final glacial stages of the last millennium. These cold events were separated by warm conditions that allowed theNothofagusforest to colonize deglaciated land. The presence of near-concurrent glacier fluctuations in Patagonia and Antarctic Peninsula indicates widespread cooling punctuated the Late Holocene, including the last millennium, across much of the extratropical Southern Hemisphere. We link this cooling to cold oceanographic-atmospheric conditions forced by a northern shift or intensification of the Southern Westerly Winds. Such scenario increased northward advection of cold Antarctic circumpolar water along western Patagonia and favored decreased upwelling of warm circumpolar deep water together with expanded sea ice around the Antarctic Peninsula.